Although it may sometimes be found foraging in open pastures close to the rainforest edge, the giant antpitta spends most of its time within the rainforest itself (2). Its diet includes large beetles, slugs and grubs, but it may also eat tadpoles and frogs, as the giant antpitta has been observed foraging near streams and stagnant puddles (2) (5).
It is thought that giant earthworms (Rhynodrylus spp.) are the giant antpitta’s preferred food. The giant antpitta has been observed pounding its beak into the soil with sudden, repeated movements and giant earthworms have subsequently been found with neat beak marks (4). Foraging has been observed throughout the day, from thirty minutes before dawn to thirty minutes after dusk (2).
The giant antpitta is thought to breed in the wet season, between February and June, as fledglings have been seen at this time and this is also when its birdsong can be heard at higher elevations (3).
In antpittas (Grallaria and Grallaricula spp.), both the male and female contribute to the nest, which is constructed using dry sticks and lined with materials including moss and dry grass. The nest is a round, open cup shape, situated no more than three metres above the ground. It is either built with many small supports, such as branches or vines, or against larger structures like fallen logs and tree stumps (3).
Birds in the genus Grallaria lay two eggs, which are turquoise to blue-green and have no markings. Both adults incubate the eggs for around 17 to 20 days and spend around 90 percent of their time at the nest. After hatching, the nestlings are fed on giant earthworms and insects. The young chicks usually fledge the nest 15 to 19 days after hatching (3).
Antpitta eggs are predated by birds, such as the turquoise jay (Cyanolyca turcosa), and other predators include the mountain coati (Nasuella olivacea) and the tayra (Eira barbara). If a predator should pass a nesting antpitta, the bird generally responds by freezing and remaining motionless, only fleeing if there is no other option available (3).